FIG. 1 depicts a schematic diagram of a portion of a typical wireless telecommunications system in the prior art, which system provides wireless telecommunications service to a number of wireless terminals (e.g., wireless terminals 101-1 through 101-3) that are situated within a geographic region. The heart of a typical wireless telecommunications system is Wireless Switching Center ("WSC") 120, which may also be known as a Mobile Switching Center ("MSC") or Mobile Telephone Switching Office ("MTSO"). Typically, Wireless Switching Center 120 is connected to a plurality of base stations (e.g., base stations 103-1 through 103-5) that are dispersed throughout the geographic area serviced by the system and to local and long-distance telephone and data networks (e.g., local-office 130, local-office 139 and toll-office 140). Wireless Switching Center 120 is responsible for, among other things, establishing and maintaining calls between wireless terminals and between a wireless terminal and a wireline terminal, which is connected to the system via the local and/or long-distance networks.
The geographic area serviced by a wireless telecommunications system is partitioned into a number of spatially distinct areas called "cells." As depicted in FIG. 1, each cell is schematically represented by a hexagon; in practice, however, each cell usually has an irregular shape that depends on the topography of the terrain serviced by the system. Typically, each cell contains a base station, which comprises the radios and antennas that the base station uses to communicate with the wireless terminals in that cell and also comprises the transmission equipment that the base station uses to communicate with Wireless Switching Center 120.
For example, when wireless terminal 101-1 desires to communicate with wireless terminal 101-2, wireless terminal 101-1 transmits the desired information to base station 103-1, which relays the information to Wireless Switching Center 120. Upon receipt of the information, and with the knowledge that it is intended for wireless terminal 101-2, Wireless Switching Center 120 then returns the information back to base station 103-1, which relays the information, via radio, to wireless terminal 101-2.
A software application at each base station controls, among other things, the task of regulating the flow of information within that cell. As is well-known in the prior art, the software application can be complex and can require periodic or sporadic updates either to replace a corrupt software application or to provide an enhanced software application.
For example, the software application controlling a base station might comprise an error caused by a mistake in the logic in designing the software application, or an error caused by the corruption of one or more bits constituting the copy of the software application stored at the base station. The latter error can be caused by, for example, lightning, electrical surges on the power supply, solar flares, etc. Alternatively, the software application in the base station might need to be updated because a new version of software application has been developed that adds a new feature to the base station.
In either case, the new software application must be installed at the base station: (1) while the base station is performing its desired functionality, and (2) in a reliable manner. For example, a base station provides telecommunications services to customers 24 hours per day, and often, as in the case of 911 calls, the urgency of the calls is such that the base station should not be removed from service while the new software application is installed. Furthermore, the installation of the new software application and the design of the base station must be such that if there are any problems with the new software application, the base station is robust and able to recover while minimizing any disruption in service to customers.
A first method in the prior art for installing a software application in a base station is for the technician to physically transport the medium (e.g., a diskette, a CD-ROM, etc.) embodying the software application to the base station and to manually install the new software application into the base station. A wireless telecommunications system can comprises thousands of base stations that are dispersed over a vast geographic region and, therefore, it can be prohibitively slow or expensive or both to dispatch a technician to each base station. Although this method for installation can be performed while the base station is running, assuming that the base station has appropriate multitasking software, the reliability of this method is not clear. For example, if the newly installed software application crashes while the technician is at the base station, the technician can quickly re-install the software application. In contrast, if the new software application crashes after the technician has left the base station, service at the base station could be disrupted for a considerable period until the technician is able to return to the base station.
A second method in the prior art involves utilizing the communications channel between the wireless switching center and the base station to transport the software application. First the new software application is stored on a computer at the wireless switching center and a technician is dispatched to each base station, in turn. In accordance with this method, the technician does not transport a medium embodying the software application. The technician does, however, manually enter commands into the base station's console directing the base station to retrieve the software application from the wireless switching center and to store it into the base station's memory. After the software application is stored, the technician directs the base station to begin executing it. If the application fails while the technician is at the base station, the technician can re-install the software application, or, if the technician suspects a programming error, the technician can direct the base station to retrieve a prior, previously-tested software application from the wireless switching center and to store it into the base station's memory.
The second method is advantageous in that it allows a software application to be installed at the base station that is very recently created, and might not have been available to the technician when th, technician was last at his or her service facility. Furthermore, this method is advantageous because it enables the technician to have access to several versions of the software application, in case one version does not work. The second method is disadvantageous, however, because, like the first prior art method, it is slow, expensive, and offer's no more reliability than the first prior art method.
A third method in the prior art involves remotely directing the base station from the wireless switching center to install and execute a software application. This method is advantageous in that it eliminates the delay and expense of dispatching a technician to the base station, and allows very-recently developed software to be installed at the base station. This method is disadvantageous, however, in that if the software application crashes, the base station can be out of service while the software application is being re-installed. And because the software application can comprise megabytes of data, re-installation can take several minutes.
Therefore, the need exists for a technique for installing a software application at a base station reliably, inexpensively, and while the base station is performing its intended functionality.